Pressure reducing and relieving valves with feedback are well known and used in many different automotive and other applications. For example, such valves have been applied to vehicular braking, steering, transmission and suspension systems.
In general, pressure reducing and relieving valves are used to selectively communicate a pressure port to be controlled with either a pressure inlet or a pressure relief port. The degree of communication between the control pressure port and either the inlet port or relief port is proportionally variable in many cases, for example by the use of a solenoid which acts against a spring. In many of these valves, a pressure from the control port is plumbed within the valve so as to exert a force on the valve spool which opposes the solenoid force, and the valve spool is balanced by the relief pressure.
Prior pressure reducing and relieving valves often required complex machining operations which contributed to a relatively high cost of such valves. The present invention provides a pressure reducing and relieving valve with few parts and relatively simple machining operations required to reduce the cost and complexity of manufacturing such valves.